From Sonic Retro
Sonic ERaZor is a hack of Sonic the Hedgehog (16-bit) created by Selbi. This hack is unlike many other hacks, featuring a heavy in-game story line, unique challenges, and never seen before gameplay mechanics. These elements are often somehow related to explosions, which is why this hack is sometimes called "What if Michael Bay directed Sonic 1".
When first released back in early 2010, Selbi stated that this hack has no goal whatsoever and any ideas he came up with just went in. Today's releases have a lot more structure and thought out gameplay elements. The difficulty has been steadily decreased between the different versions, mostly due to some negative feedback regarding the first releases, although they all have an above average difficulty, and is therefore regarded by many as quite interesting and challenging, if not frustrating.
A notable aspect about this hack is that it contains many cutscenes, chapter screens and story screens. The game's first scene after the title screen is entirely a cutscene.
Sonic ERaZor's levels are based on those of its source game. The level order, however, was completely redone.
The first level of this game starts even before the actual game begins. It was designed to teach players through the various unique aspects of this game they will face later on. To do that, Information Monitors are spread around the level, which can be activated by pressing A while standing in front of them. Upon doing so, a small window will appear on the screen and write out the information. The level contains guidelines to the controls, the Inhuman Mode, the Hard Part Skippers, Trial-and-Error sections, and Gravity Control. This entire stage can be skipped by jumping into the ring on the left of the player, as he enters the stage.
A short cutscene featuring Sonic running at high speed through a Green Hill Zone based level with a hot palette. While that Sonic is being chases by a Buzz Bomber, which shoots exploding bullets at him. At a special point, Sonic breaks open an S-Monitor, which gives him the Inhuman Mode. The Buzz Bomber touches spikes and explodes a few seconds later. The Inhuman Mode is being demonstrated by shooting a bullet, which leads Sonic to a special platform. At the end of the sequence Sonic jumps into a giant ring and the palette turns dark and disappears. A story screen will appear to explain the back story.
The overworld of this hack. The player can go to the options menu by using the red spring on the very left, play the tutorial again, or, of course, select the level they want to play, by jumping into tubes. On the first run however, the player needs to unlock doors, which is done by beating levels. With each beaten level, the player may advance to the next level.
Night Hill Place
This is a darker version of the source game's Green Hill Zone. Sonic can't defeat Selbi's altered badniks in the waterfall section. The patient player can lure them over to the left to destroy them, or the impatient can simply try to avoid colliding with them. There is also a hidden S-monitor in that section, which transforms Sonic into the Inhuman Mode, a state in which he is invincible to absolutely everything and doesn't lose rings, unlike official games' Super Sonic or Hyper Sonic. At the end of this level is a boss fight with a Crabmeat, which shoots a lot of exploding balls.
Green Hill Place
This level takes place right after the Crabmeat battle, where Sonic enters a brighter and more classic-looking level, the original Green Hill Zone, with some differences though. Many enemies in this section are covered in explosions or related to explosions otherwise, making it difficult for them to be destroyed without the player taking a hit themselves, but this is manageable because Sonic only loses twenty of his rings per hit instead of all of them. At the end of this level is a boss fight with a super speedy Dr. Eggman with 3 wrecking balls, a modified version of the classic GHZ boss battle. Just be careful not to jump over springs, or sudden screen lock changes will kill Sonic.
Based off the original Special Stages, the Special Place is about Sonic being in a labyrinth. Unlike the original one however, this one doesn't rotate. Instead the player is required to carefully move Sonic through the stage and avoid the many GOAL blocks. If Sonic touches one of these, the stage won't end though, but he will be teleported to the last check point he collected. At the end of this stage, the player will collect 4 emeralds at once, even though they don't have any usage for the later game. This is also mentioned in the story.
Half-way through this level, which is based on Marble Zone, Sonic is forced to activate an S-monitor. Unlike other S-monitors in the game however, this one disables all of his special abilities and causes him to lose rings extremely quickly while standing still (but slower while moving). Think of the movie Speed, but with a hedgehog, because the player dies upon reaching zero rings. Immediately after transforming, the player must navigate through a maze with spiked walls, ceilings and floors - and these spikes will teleport Sonic to the beginning of the course every time he touches them and remove even more rings. There is no boss at the end of this level.
As soon as this level begins, the scrolling of the screen is quite different from that of a usual Sonic level. It's like Jungle Zone Act 2 from the Sega Master System version of Sonic 1 version: As soon as Sonic lands on higher ground, the screen will rise and lock; if he then hits the new bottom of the screen, he will die. Hit a checkpoint to reverse the direction of scrolling. To get to the goal, do the counter-intuitive thing and avoid the rings: They lead to dead ends (which are marked with 1-up monitors). There is no boss at the end of this level as well.
The second Special Stage also follows the same idea as the first special stage, being a non-rotating labyrinth the player must navigate through. This one stage has a different direction though: Upon touching a certain block, Sonic will automatically fly up and down, restricting the player to only the left and right buttons. The movement can be reversed by touching an UP or DOWN block and checkpoints are scattered around the level. At the end of the stage, the remaining 2 emeralds need to be collected. It must be done without hitting the wall, otherwise the already collected emerald will be lost and needs to be collected again.
Scar Night Place
Before the actual level starts, a cutscene is being shown in which Eggman goes to the machine that produces the Walking Bomb enemies. He presses a huge button, changing the color scheme of the Walking Bombs and also produces them at a faster rate, while laughing. After that the actual level starts, which is divided into two different sections.
The first section is similar to Night Hill Place, starting off with a normal level where rings can be collected (however, there are no enemies). After that comes a unique recreation of the Walking Bomb, which was seen in the cutscene. Upon detonating, it will expose a lot of shrapnels in a random pattern, making it a rather unpredictable boss. It also doesn't destroy itself after only exploding once, forcing the player to play along until boss finally destroys itself.
The second section takes place right after the boss has been defeated. Pressing a button will cause the walls to start blinking red, as they are now harmful and must be avoided. Sonic is granted the ability he has been taught in the tutorial level, the ability to control his gravity by pressing A. In a similar manner as the stages before, the player must navigate Sonic through this huge maze and do some mini challenges from time to time.
This is the final boss. At the beginning, a lot of big machines can be seen exploding with an increasing amount of explosions. The actual boss is a harder version of the original final boss, because the crushers are moving at the same time the purple sparks are falling down, which will explode once they hit the ground.